It is known in the art that human performance, in work or athletic competition, is dependent upon maximal muscle efficiency. Muscles function most efficiently in an optimized cellular environment which is defined as:
1) Homeothermic temperature--37.degree. C..+-.1.degree. C. PA1 2) Homeostatic Ph range--7.4.+-..2 PA1 3) Adequate/Abundant Energy Sources (glycogen/glucose) PA1 4) Adequate/Abundant Oxygen Sources PA1 5) Maximized Blood Circulation (to bring in nutrients, oxygen; and remove waste products-lactic acids and CO.sub.2) PA1 1) Carry blood flow to the skin to dissipate excess heat of muscle metabolism. PA1 2) Carry blood flow to the muscle to replenish glycogen/glucose stores, oxygen, and remove acidic waste products (Lactic acid and CO.sub.2). PA1 1) Evaporate perspiration and cool the body and/or PA1 2) Retain heat from selected body portions and wick moisture away for rapid evaporation, thus keeping the garment dry and warm.
During human work (or athletic performance) muscle metabolism creates a tremendous heat load which must be dissipated by the human thermoregulatory system.
The skin, through the production and evaporation of perspiration, dissipates this heat load. Radiation, conduction, and convection contribute to this heat dissipation. However, in the active athlete, 80% of this heat dissipation is accomplished by the evaporation, at the skin level, of perspiration.
Humans (and their muscles) function best in a homeothermic state, (37.degree. C..+-.1.degree. C.). Thus the proper management of this "heat load of metabolism" assumes a high priority in the circulatory physiologic response of athletes in competition (or in high-intensity workers).
The circulation (blood flow) eventually finds itself with two high demand requirements:
A competition then develops between the skin and muscle for blood flow in the high performance athlete or intense worker.